The present invention relates to a vehicle alarm system.
The vehicle alarm system of the invention produces an alarm for an abnormal condition of an operating part of a vehicle such as, for example, lowered tire pressure, shortage of engine oil, overheated cooling system fluid, and so on, by making use of the audio signal circuit of the audio reproduction system of the vehicle.
Recently, in vehicles such as, for example, automotive vehicles, if an abnormal condition which may be dangerous to life or property is detected in an operating part such as, for example, the lighting system, the engine system, the brake system, and so on, when starting or driving, an alarm system warns of such abnormal condition. The known alarm systems provide either a visual alarm via a lamp display or an audible alarm via a buzzer, or the like.
The known alarm systems have disadvantages. The visual alarm may escape the notice of the operator of the vehicle. The audible alarm makes it difficult for the operator of the vehicle to judge the type of abnormal condition detected, upon hearing the alarm, since the tone of alarm cannot be varied. Furthermore, installation of an audible alarm system is very complicated and expensive, if it is attempted to install different sound sources for each type of said abnormal condition.
The principal object of the invention is to provide a vehicle alarm system which produces alarm signals of different frequency tones in accordance with the sources of abnormal conditions.
An object of the invention is to provide a vehicle alarm system of simple structure which is inexpensive in manufacture and provides an alarm signal in the audio signal circuit of the audio reproduction system of the vehicle.
Another object of the invention is to provide a vehicle alarm system which selects a preferred one of a plurality of alarm signals when a plurality of abnormal condition signals are simultaneously received.
Still another object of the invention is to provide a vehicle alarm system which is of simple structure, inexpensive in manufacture and installed in new and existing vehicles with facility and convenience.
Yet another object of the invention is to provide a vehicle alarm system of simple structure, which functions efficiently, effectively and reliably to provide alarm signals, via the audio reproduction system of the invention, indicative of abnormal conditions in different operating parts of the vehicle.